RU64274U1 - DEVICE FOR LOW-FREQUENCY ACOUSTIC INFLUENCE ON THE PERFORATION ZONE AND OIL LAYER IN THE BOTTOM-HOLE ZONE - Google Patents

Abstract

The utility model relates to the oil industry and can be used to intensify oil production during the development of oil fields and the cleaning of water and ore wells. Provides an increase in the intensity of acoustic exposure in the bottomhole zone of the casing string, and especially in the reservoir. The essence of the utility model: The device includes a low-frequency acoustic emitter of a composite type in the form of a piezoceramic rod and a passive back plate placed in a sealed enclosure, an active radiating plate in the form of a disk outside a sealed enclosure having two flat radiating surfaces perpendicular to the longitudinal axis of the device. The technical result of the claimed utility model is the creation of a radiator design with a significantly reduced length. The technical result is achieved due to the fact that the utility model claims a composite acoustic emitter, which in addition to the piezoelectric rod contains two metal concentrators and two cylindrical ribbed bimetallic waveguides, the concentrators being connected by one end to the piezoelectric rod and the other end to one of the bimetallic ribbed waveguides , and the waveguides are made in the form of a cylindrical rod of light metal, the surface of which is covered with a screw thread, with the help of Strongly wherein the rod is uniformly along its length has a heavy metal washer, a second end of the waveguide connected to the passive plate and the other end of the other waveguide with an active plate radiator.

Description

The utility model relates to the oil industry and can be used in the development of oil fields and the cleaning of water and ore wells.

There are various methods and devices that create mechanical effects on the perforation zone of the casing and the oil reservoir located behind it. A significant number of them were analyzed upon filing by the authors of this utility model of application No. 2003132257 of November 05, 2003. According to which the Federal Service for Intellectual Property granted patent No. 2263203 with priority of November 05, 2003.

The list of documents cited in the search report contains:

RU 2129659 C1 of 04/27/1999

RU 2161244 C1 dated December 27, 2000

SU 1402991 A1 dated 06/15/1988

SU 1402991 A1 dated 07/30/1988

WO 96/12409 A1 of 04/22/1991

US 5727628 A1 of 03/17/1998

US 4184562 A1 of 01/22/1980

Additionally reviewed documents:

SU 1413241 A1

RU 2.047.280 C1

US 4,469,175 A dated 09/04/1984

RU 2192651 C2 dated 11.27.2002

RU 2055979 C1 of 03/10/1996

The prototype for the claimed utility model is the device claimed in patent 2263203 with priority dated November 05, 2003. The essence of this invention: the device includes an acoustic emitter of a composite type in the form of a piezoceramic rod and a passive back plate placed in a sealed enclosure, an active radiating plate in the form of a disk located outside the sealed enclosure and having two flat radiating surfaces perpendicular to the longitudinal axis of the device. In this case, the acoustic emitter is equipped with at least one metal reflector with flat surfaces parallel to the flat surfaces of the active emitting lining, mounted to move along the axis of the device and fixation in a predetermined position.

The device is used to work inside the casing in the perforation zone of the bottomhole zone. Such a device was manufactured and effectively used for low-frequency wave impact on the perforation zone and productive oil reservoir at the fields in Tatarstan Tat-RITEK-oil in June-July 2005 (production well No. 2576) and October-December 2006 (production wells 2567 , 3609, injection 2504). The operating frequency range of this device is in the vicinity of 600 ÷ 800 Hz. The device uses a symmetric composite emitter, in which the central section consists of piezoceramic packets and smooth round metal rods.

It is known that the absorption of elastic vibrations in the earth's environment increases with increasing frequency of vibrations. Therefore, to increase the radius of the vibroacoustic impact on the oil reservoir, a further decrease in operating frequencies is necessary. The calculations are given,

for example, in the monograph by O. L. Kuznetsov, E. M. Silkin, J. Chilingar “Physical fundamentals of vibration and acoustic impacts on oil and gas layers”. (Publishing house "MIR" Moscow 2001). It follows from the scientific material cited that it is possible to excite natural frequencies in the productive layer in the range of 90-200 Hz, the magnitude of which depends on the thickness of the formation. This phenomenon should also lead to an increase in oil recovery.

In the general case, a decrease in the operating frequency of an acoustic emitter, including a composite one, is associated with an increase in its size. For a composite emitter - with an increase in its length.

The calculation of the composite emitter is given in numerous scientific sources related to the creation of sonar antennas, for example, Kamp L. Underwater acoustics M .: MIR, 1972, pp. 50-56; Sverdlin G.M. Hydroacoustic Transducers and Antennas: A Textbook. - L .: Shipbuilding, 1988.

Figure 1 shows a picture of the equivalent half-wave composite resonator, and figure 2 the amplitude of the vibrational displacement of the elements of the resonator.

1 - passive pad

2 - central section

3 - active pad

The resonant frequency is found from any one equation:

tgk ₂ tgk ₃ b = Zm ₂ / Zm ₃

or

tgk ₂ qtgk ₁ L = Zm ₂ / Zm ₁

k ₁ is the wave number in medium 1. k ₁ = 2π / λ ₁ = 2πf _p / s ₁ ;

k ₂ is the wave number in medium 2. k ₂ = 2π / λ ₂ = 2πf _p / s ₂ ;

k ₃ is the wave number in medium 3. k ₃ = 2π / λ ₃ = 2πf _p / c ₃ ;

f _p - resonant operating frequency

Z ₁ , Z ₂ , Z ₃ - mechanical impedances, respectively, are equal to ρ ₁ c ₁ S ₁ , ρ ₂ s ₂ S ₂ , ρ ₃ s ₃ S ₃ .

C is the propagation velocity of sound vibrations in media 1, 2, 3.

S ₁ , S ₂ , S ₃ , is the cross-sectional area of elements 1, 2, and 3.

ρ ₁ , ρ ₂ , ρ ₃ , is the area of media 1, 2, 3, respectively

With a symmetric composite emitter c ₁ = c ₃ , ρ ₁ = ρ ₂ and the masses of the plates 1 and 3 are equal.

The analysis shows that a decrease in the resonant operating frequency can be achieved mainly by increasing the length of the middle (central) section of the vibrator. The same effect can be achieved by reducing the “rigidity” of the central section 2 by reducing its cross section or by choosing a “soft” material with a small Young's modulus. This leads to a decrease in the ratio Zm ₂ / Zm ₃ or Zm ₂ / Zm ₁ .

In practical terms, these possibilities are very limited. As metals, only metals can be used. (Really - only steel). The internal diameters of the production casing are 5 ÷ 6 inches, i.e. 127 ÷ 152 mm.

Given the thickness of the sealing case, the diameter of the central rod, consisting of piezoceramics or magnetostrictive material, cannot exceed 70 mm.

The device is a prototype, has a length of 2.5 m with an outer diameter of the sealing case 70 mm and an inner diameter of 50 mm It has a central section consisting of piezoceramic bags and round duralumin rods. Reducing the operating frequency to 175 Hz without changing the design of the central section,

would automatically require a four-fold increase in the length of this part of the device, i.e. up to ≈10 meters.

It is impractical to make the central section thin, because the mechanical strength of the emitter will be impaired.

In radio devices, delay lines made up of L, C low-pass filters with lumped parameters, the so-called K, M, or T links, are widely used. Figure 3 shows the delay line of several such links of type K.

L is the inductance of the electrical link

With _e - the capacity of the electric link

The propagation time of electrical signals along such a line in the low-frequency region where n is the number of links.

A mechanical delay line can also be created, as there is a similarity between the formulas for electrical and mechanical processes. This can be used to obtain a low speed with ₁ in the central section of the composite emitter. The calculations are given, for example, in Harry F. Olson's book “Dynamic Analogs” (State Publishing House of Foreign Literature, Moscow 1947 p.53 and 103)

An equivalent mechanical circuit consists of masses and elastic elements.

Such a line is created from a rod of variable cross section.

The role of inductance in electrical formulas is played by mass, in mechanical formulas, the role of capacitance is mechanical compressibility C _m . The larger the mass and the thinner the rod, the lower the speed of propagation of elastic waves along the rod. The waveguide configuration is shown in FIG. Such a waveguide is called "ribbed."

The technical result of the claimed utility model is the creation of a composite emitter design that provides a significant reduction in the operating frequency. Compared with the prototype with approximately the same lengths of the emitters, the achievable reduction in frequency reaches up to 3 times.

The technical result is achieved due to the fact that the device contains an acoustic emitter of a composite type, consisting of two piezoceramic or magnetostrictive cylinders, which are connected to one another through a sealing cylinder, and mechanically connected through a conical hub to a "bimetallic" ribbed waveguide. A bimetallic waveguide is named because it is made of two metals that are significantly different in their physical properties. The second end of one "ribbed" waveguide is mechanically connected to the active plate of the emitter. The surface of a round rod made of light metal is coated with a thread, with the help of which “ribs” —washers made of heavy metal — are evenly placed on the rod along its length.

The metal for the rod is preferably aluminum alloy or titanium. "Ribs" are preferably made from brass, copper or steel.

The configuration of the ribs is chosen so as to provide the maximum value of the concentrated mass and maximum compressibility With _m . On the outside, the structure is sealed.

Figure 5 presents the design of the claimed utility model.

The device includes an acoustic emitter of a composite type, containing one or more cylindrical piezoceramic or magnetostrictive packets 1 and 2, a symmetrical coupling 3, matching conical hubs 4 and 5, bimetal ribbed waveguides 6 and 7, active pad 8, passive pad 9, sealing protective housings 10 and 11, sealed connector 12, cable KG3 13, reflector holder 14 and reflector 15.

The operation of the device is as follows. The device is lowered on the cable 13 into the casing in the perforation zone 16.

The excitation voltage in the region of the resonant frequency of the emitter is supplied through the cable to the emitter. Inside the fluid volume between the active patch and the reflector, a field of standing waves arises.

Due to the fact that the stiffness of the steel walls of the casing string is significantly greater than the elasticity of the liquid, and the total area of the holes is much smaller than the area of the side surface of the casing string, the increase in the intensity of the effects of vibrations inside the resonating volumes can be significantly larger compared to the intensity created by the emitter in free space.

Claims (1)

A device for acoustic impact on the perforation zone and the oil reservoir in the bottomhole zone, including a composite type acoustic emitter in the form of a piezoceramic rod and a passive back plate placed in a sealed enclosure, an active disc-shaped radiating pad outside the sealed enclosure and having two flat radiating surfaces, perpendicular to the longitudinal axis of the device, while the acoustic emitter is equipped with at least one metal reflector with flat surfaces, parallel flat flat surfaces of the active radiating lining, mounted for movement along the axis of the device and fixing in a predetermined position, characterized in that the composite acoustic emitter further comprises two conical metal concentrators and two cylindrical bimetallic ribbed waveguides, the concentrators being connected to the piezoceramic rod by one end and the other the end face with one of the bimetallic ribbed waveguides, and the waveguides are made in the form of a cylindrical rod of light of metal, the surface of which is coated with a thread, with the help of which washers of heavy metal are placed uniformly on the rod along its length, the second end of one waveguide is connected to the passive overlay of the emitter, and the second end of the other waveguide with an active overlay of the emitter.